Technical Field
The present disclosure relates generally to an engine torque control method for a vehicle, and more particularly, to an engine torque control method for a vehicle that quantifies slip of a clutch and accurately filter-controls engine torque.
Description of the Related Art
A Dual Clutch Transmission (DCT) is a system in which the flywheel of an engine and the dry clutch of a transmission are directly connected to each other. Accordingly, appropriate driving force can be transmitted to a driveshaft, that is, an output shaft, by applying clutch torque to torque from the engine. If the driving force is not smoothly transmitted, engine flare may be generated, and if a clutch is excessively engaged at too low of an engine speed, an engine stall may result.
FIG. 1 is a graph showing a conventional engine torque change in tip-out during shifting, and FIG. 2 is a graph showing a conventional engine torque change in tip-out after tip-in during creeping. As shown in FIGS. 1 and 2, in tip-out in which a driver lifts his or her foot off an acceleration pedal for deceleration, it can be seen that flare is generated, whereby the engine revolutions per minute (RPM) keeps increasing and then decreases after a predetermined time passes due to excessive torque which is generated by engine torque temporarily exceeding clutch torque.
Conventionally, a Transmission Control Unit (TCU) filter-controls engine torque on the basis of torque from an engine. However, in some cases, a clutch is rapidly disengaged to protect a vehicle regardless of the state of an engine when there is a possibility of engine stall.
In this situation, an Engine Control Unit (ECU) receives state information, such as opening/slipping/locking of a clutch, but cannot receive accurate information about the state of a transmission. Accordingly, when torque is generated by inappropriately operating an engine with a clutch open, engine flare is generated.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.